This invention relates to a cycloaliphatic acrylate composition containing mixtures of dicyclopentadiene (meth) acrylate, acrylates which comprise the mono and di (meth) acrylates of tri, and tetracyclopentadiene, copolymers of acrylic acid or methacrylic acid with adducts by cyclopentadiene with isoprene and/or piperylene, and a mixture of polyacrylates having the repeating unit ##STR3## where R.sup.1 is hydrogen or ##STR4##
R.sup.2 is CH.sub.2 .dbd.CZ--C(O)--O--
Z is H, or methyl
n is 0, 1 or 2
m is 0 or 1 and when m is 0 there is a double bond present. The invention also encompasses thermosetting resin compositions containing the acrylate composition.
Dicyclopentadiene acrylate (DCPDA) is known from U.S. Pat. No. 2,414,089 dated Jan. 14, 1947.
It is known from British Pat. No. 1,114,585; Modern Plastics, Sept. 1976, pages 95-103; Rubber World, June 1974, page 42 and German Pat. No. 1,234,027 that a distilled or a substantially pure dicyclopentadiene acrylate can be used alone or blended with other unsaturated monomers to make thermoplastic polymers, rubbers, or for crosslinking unsaturated polyesters.
The use of distilled dicyclopentadiene alkenoate concentrate to cure or crosslink vinyl ester resins and polyester resins is known from Ser. No. 814,358 and Ser. No. 814,359 both filed on July 11, 1977.
According to U.S. Pat. No. 2,414,089 (49), DCPDA can be prepared by esterification of dicyclopentadienyl alcohol or dicyclopentadiene (DCPD), or by ester exchange. Recovery of pure DCPDA is accomplished by dilution of the crude reaction mixture to reduce viscosity and density, washing with basic solutions and water, removal of diluent and distillation under high vacuum. In Brit. Pat. No. 1,114,585 (68) and U.S. Pat. No. 3,427,363 (60) specific examples are given for the preparation of pure DCPDA. The yield of DCPDA based on DCPD does not exceed 86.6%. German Pat. No. 1,954,548 (71) addresses itself to solving a specific problem of the general process, namely the elimination of emulsion formation during work-up.
While DCPDA has been known for over 30 years, no significant commercial use has developed because the cost of production has been prohibitive for most uses. The reason for the high cost is the requirement for a distilled product free of difunctional compounds and polymers for thermoplastic polymer applications and for a low-colored product for thermoset uses. Distillation of DCPDA is difficult because of the high reactivity of the acrylate bond and the propensity to crosslink of the cyclopentene double bond, and because of the high boiling point of 280.degree. C./760 Mm Hg or 100.degree. C./1.7 MM Hg. Even with well inhibited systems, distillations are limited to about 120.degree. C. Furthermore, the polymers formed during the process and during distillation are difficult to handle because they are partially crosslinked or gelled.